Slide changing apparatus



' Oct. 28, 1941.

J. A. DARWIN SLIDE CHANGING APPARATUS Filed April 26, 1940 5Sheets-Sheet l Oct. 28, 1941. J. A. DARWIN 2,260,660

SLIDE CI-IAIKIY'JINGr APPARATUS Filed April 26, 1940 5 Sheets-Sheet 2Oct. 28, 1941.

J. A. DARWIN 2,260,660

SLIDE CHANGING APPARATUS Filed April 26, 1940 5 Sheets-Sheet 3 Oct. 28,1941.

J. A. DARWIN 2,260,660

SLIDE CHANGING APPARATUS 5 Sheets-Sheet 4 Filed April 26, 1940 Oct. 28,1941. 4. A. DARWIN SLIDE CHANGING'APPARATUS Filed April 26, 1940 5Sheets-Sheet 5 MpHHWHHIHWHHHWHHHHHIHW HI A h||| H! H jvwwm Jase ah A-Darwin moon/M30 I Patented Oct. 28, 1941 UNITED STATES PATENT OFFICE2,260,660 SLIDE CHANGING APPARATUS Joseph A. Darwin, East Orange, N. J.Application April 26, 1940, Serial No. 331,830

30 Claims.

The present invention relates to improvements in slide changingmechanism adapted for use with projectors, magic lanterns, and the like.

An object of the invention is the provision of means for accommodatingslides of different thicknesses and materials.

Another object is to provide a mechanism par. ticularly adapted toaccommodate slides having metal casings or frames. This type of slide isuniversally used at the present time, since it can withstand repeatedusage without the necessity of replacement.

I have found, however, from actual experience that the metal frames havecertain disadvantages which affect the efficiency of the slide changingmechanism, unless means are employed to compensate for these defects.For instance, the metal frames are usually manufactured in quantityproduction from sheet metal, and, in many instances, these frames haveWarped or bellied portions, as well as other projections, which mayinterfere with the progress of the slides through the slide changingmechanism.

The mechanism of the present invention is of the closed circuit type,including a frame upon which are supported a pair of spaced slideretaining magazines. The frame is also provided with front and rearslide tracks which connect adjacent ends of the magazines, and means areemployed for progressively feeding the slides forwardly in themagazines. As each slide reaches the front of its respective magazine, aslide carrier engages the outside edge of the front slide and shifts ittransversely of the magazine into its adjacent slide track, whereby theslides are intermittently shifted on the tracks to the other magazine.

I have ascertained that because of the projections or warped portions ofthe metal frames of the slides, the front slide may become jammed orcaught in its adjacent slide as it is being shifted laterally thereofinto the slide track. In other words, the front slide may not be free tomove transversely of its adjacent slide as it is being shifted into theslide track, either because of these'imperfections in its own frame orthat of the adjacent slide.

The present invention is designed to eliminate this ojectionable featureby providing means for positively rocking the front slide just prior toits transfer to the slide track. This rocking motion or action is suchas to separate each side of the front slide from its adjacent slide, sothat it will entirely clear any projection or warped portion on the nextslide as it is shifted transversely thereof to the slide track. Therocking action is not only transmitted to the end slide, but also to theadjacent slides in varying degree, whereby the slides as they approachthe front of the magazine, will be rocked relative to their adjacentslides, and thereby be free to move into the slide track without jammingor catching on the adjacent slide.

A further object of the invention is to provide an improved pushermechanism for pushing a slide into the rear end of its respectivemagazine as it is received from the slide track. This pusher mechanismis particularly designed to take advantage of the resiliency andspringiness of metal and paper slide frames, as well as frames of othermaterials which have these characteristics. I have found that a magazineof slides having metal frames possess such an amount of springiness thatit is not necessary to provide a spring means associated with the pushermechanism for constantly urging said mechanism against the rearmostslide in the magazine. This is also true of slides having paper orcardboard frames. Such frames also have a substantial amount ofresiliency and springiness, due primarily to the fact that airpenetrates between adjacent slides and forms air pockets. Furthermore,the porosity of the paper frames assists in the springy and resilientaction of the slides when acted upon by the pusher mechanism. Due tothese characteristics, the slides may becompressed in the magazine to aconsiderable extent by the pusher mechanism. Because of this, it is notnecessary that a predetermined or specific number of slides be placed ina magazine to assure the proper functioning of the pusher mechanism. Inother words, the number of slides in one magazine may vary with those inthe other magazine, the only requisite being that there be a sufficientnumber of slides in a magazine to permit the pusher mechanism totransmit the pushing action to the slides at the front of the magazine.

Another object is to provide apparatus which is synchronized with thepusher mechanism for operating the slides carriers to shift the frontslides out of the magazines just prior to the operation of the pushermechanism for inserting slides into the rear end of the magazines.

A still further oject is the provision of means carried adjacent thefront of the magazines and above the normal path of the slides forcontacting the upper edge of a slide which has been accidentally raisedabove its normal level,

and return the slide to its normal position prior to its movement intothe slide track.

Another object is to provide one or more adjustably mounted guide platesadjacent the slide track and constituting abutments for engaging theslides as they move into position to be shifted in the slide track.These plates are capable of being adjusted relative to the slide trackto accommodate slides of different thicknesses and to take up anyclearance in the slide track which might otherwise permit rattling orlateral movement of the slides as they pass through the track.

Aonther object is to provide magazines which are capable of being easilyand quickly inserted and removed from the slide changing frame, thuspermitting a new set or series of slides to be expeditiously substitutedfor a set which has been exhibited.

A further object is the provision of an adjustable spacer which may beplaced in a magazine to take the place of a plurality of slides, in theevent the operator is not supplied with sufficient slides to entirelyfill each magazine.

With the foregoing and other objects in view, the invention will now bemore fully described, reference being had to the accompanying drawings,in which:

Figure 1 is a perspective view of the complete slide changing machineshowing a projector in operative position in dotted lines;

Figure 2 is a view of the rear end of the machine showing the rear slidetrack;

Figure 3 is a broken side view with the magazine removed;

Figures 4 and 5 are detail views of the pusher mechanism;

Figure 6 is an end view of the front of the machine showing the frontslide track and slide carrier;

Figure 7 is a plan view ofthe slide carrier;

Figure 8 is a section on line 8-8 of Figure 7;

Figure 9 is an end view of the carrier;

Figures 10 and 11 are front and rear views of a slide encased in a metalframe;

Figure 12 is a section on line l2-I2 of Figure 11;

Figures 13, 14, 15 and 16 are enlarged fragmentary views showing therocking movement transmitted to a slide as it is being transferred fromthe front of a magazine to a slide track;

Figure 17 is a view showing a modified means for operating the slidechanging mechanism;

Figure 18 is a side elevation of one of the magazines or trays;

Figure 19 is a fragmentary view of an end of the cover for the magazine;

Figure 20 is a fragmentary view showing the cover applied to themagazine;

Figure 21 is an end view showing the cover applied to the magazine; I

Figure 22 is a fragmentary view of an end of the magazine;

Figure 23 is a side elevation of a spacer;

Figure 24 is an end view thereof Figure 25 is a section on line 25-25 ofFigure 23, and

Figure 26 is a diagram of the electrical circuit and switchescontrolling the operation of the apparatus.

Referring now to the drawings, the numeral l0 designates generally myslide changing apparatus consisting of a main supporting frame II, afront auxiliary frame l2, incorporating a front slide track, and a rearauxiliary frame I 3 having formed therein the rear slide track of theshifted into the rear slide apparatus. A pair of slide retainingmagazines or trays l4 and I! are detachably supported in spaced relationon the frame II. The tray I will hereinafter be designated as the supp ymagazine, the tray l5 being the receiving magazine.

The present invention is of the closed circuit type of slide changingmechanism, in which the slides l8 are capable of being continuouslymoved in a circuit through the mechanism. It will be observed that themagazines I4 and I5 are arranged in spaced parallel relation, and thatthe frame is constructed to provide an enclosed space or opening. Thisis to accommodate a projecting apparatus, and since the projector formsno part of the present invention, this is merely shown in dotted linesin Figure 1, in order that the structure of the present machine will notbe obscured.

With the present construction, it will also be observed that themovement of the slides in magazine H is the reverse of the movement inmagazine 15, as indicated by the arrows in Figure 1. That is, during theoperation of the machine, the slides will be progressively moved inmagazine [4 toward the front slide track l2. front slide in magazine Mwill be initially shifted into the entrance portion of the front slidetrack and momentarily maintained in this position. Thereafter the nextslide, as it reaches the front of the magazine I, will be shifted intothe slide track, and in so doing, will transmit a further transverseshifting movement to the first slide. As will hereinafter be describedin detail, each slide will be shifted to and retained in the frontwindow ll of the plate I8, where it will be projected onto a screen (notshown) by the projector in the usual manner.

After a slide has been exhibited, the mechanism will continue to shiftit laterally in the front slide track until it is in alignment with thereceiving magazine l5. Thereafter a suitable pusher mechanism will pushthe slide into the rear end of the magazine I5, where it will beprogressively fed to the front thereof and then track. This operationmay be continued until all of the slides in the two magazines have beenexhibited. Thereafter the magazines or trays l4 and I5 may be easily andquickly removed from the main frame II, and another set of trayscontaining a new series of pictures may be inserted in the apparatus andshifted through the magazines and slide tracks, as above described.

Referring particularly to Figures 1, 2, 3, and 6, it will be observedthat the main frame ll comprises a pair of longitudinally extendingframe members or rails [9 of substantially angle iron formation. The topflange 20 of each rail constitutes the supporting surface upon which oneof the magazines is directly positioned and supported. The other flange2| projects downwardly and constitutes the outside border of the mainframe extending between the auxiliary frame members and slide tracks.

A pair of cross frame members 22 and 23, also of angle iron formation,have their ends rigidly secured to the end portions of the longitudinalframe members l9 to form therewith a rigid substantially rectangularframe construction. The horizontal flanges 24 and 25, respectively, ofthe cross frame members 22 and 23, constitute shelves forming the lowerportions of the auxiliary frame members l2 and I3.

Referring to Figures 1 and 2, there is disclosed n detail the rear framel3 within which is The mounted the rear slide track connecting the frontof the receiving magazine l and the rear of the supply magazine I4. Asstated above, the horizontal shelf 25 constitutes the lower portion offrame l3 and is provided with a longitudinally extending groove 26constituting the lower portion of the rear slide track. This grooveextends entirely across the rear of the frame section l3. The inner wallof this groove is broken away at the point where it overlaps themagazines. In other words, the base of the groove is flush with thebases of the magazines to permit the slides IS in magazine l5 to bemoved out of the magazine into the groove, so as to be in position to beshifted laterally through the groove to magazine l4. Likewise, the innerwall of groove 25 is eliminated at the point where the groove crossesthe magazine l4. This is to permit the slides to be pushed into the rearend of magazine H as they are shifted from the intermediate portion ofthe groove 26 into alignment with said magazine.

The present machine is capable of accommodating slides of differentthicknesses, that is, it is adapted to accommodate slides havingrelatively thick metal frames, as well as slides having paper frames,which usually are of considerably less thickness than the metal. slides.For this reason, the groove 26 is of a width to accommodate the thickestslides, that is those having metal frames. In order to prevent theslides Hi from rattling or moving laterally as they are shifted in thegroove 28, means are provided to contact and exert pressure on the frontof the slides as they are shifted in the slide track. This meanscomprises a longitudinally extending bar 21 slidably supported on theshelf 25, and provided with pins 28 which are received within openingsin posts 29. These posts are supported upon the shelf 25, and coilsprings 38 are mounted on the pins 28 and interposed between the bar andtheir respective posts so as to exert inward spring pressure on the bar21. Thus the bar 21 will not only constitute an additional guide means,but will tend to take up any clearance in the groove by pressing theslides against the inner wall of the groove 26 and thereby prevent anyrattling or lateral movement of the slides as they pass through theslide track. This will be true, regardless of whether the slides areencased in metal, paper, or any other type of frame. It is to beunderstood, however, that the pins 28 may be adjusted relative to theposts to control the inward movement of the bar 21. In other words, thebar is not permitted to entirely close the groove and constitute anobstacle to the slides as they pass through the slide track. Anysuitable stop means may be employed to control the inward movement ofthe bar, depending upon the thickness of the slides that are being used.

The frame I3 is provided with an upper cross bar or rail 3|, withinwhich is formed a longitudinally extending groove 32 positoned inalignment with the groove 26 and cooperating therewith to form the slidetrack. The rail 3| is rigidly connected to and supported by interiorposts 33, 34, and end posts 35 and 38. These end posts are ofsubstantially L-shape formation and have inwardly extending wings orflanges 31 and 38, respectively. The posts 33 and 34 likewise haveinwardly extending wings 39 and 48, respectively. Each set of wingscooperates with a corresponding set on the front frame l2, to securelymaintain its respective magazine detachably supported in the main frameagainst lateral displacement. For instance, posts 4|, 42, on the frontframe 12 have rearwardly extending wings 43 and 44 in line with thewings 31 and 39 for maintaining magazine l5 in operative position.

In axsimilar manner, thefront frame I2 is provided with posts 45 and 48having rearwardly extending wings 41 and 48, respectively, cooperatingwith wings 38 and 48, to receive and position' magazine l4 in the frame.It will be observed (see Figures 13 to 16) that each wing is either cutaway or provided with a projection forming a shoulder 49, to limit thelongitudinal movement of its respective magazine in the frame ll. Withthis construction, it will be apparent that each magazine with its setof slides l8 may be easily inserted and removed in the slide changingmechanism. The specific structure of the magazine or tray will bedescribed in detail hereinafter.

In addition to employing the spring pressed guiding bar 21, the rearframe I3 is also provided with a pair of plates 58 and 5| adjustablymounted on the shelf 25 (see Figure 1), Plate 58 is in line with themagazine l5 and constitutes an abutment for engaging the slides as theyare movedinto position to be shifted in the slide track. The plate 58constitutes a guard for preventing accidental removal of the slides asthey reach the slide track. The plate 5| also constitutes a guide on theother side of the bar 21 to assist in guiding the slides as they aremoved into position to be pushed into the magazine l4. Each of theseplates is slotted so that by loosening the fastening means 52, the platemay be adjusted to take care of slides of varying thicknesses.

Referring now to Figures 1, 3, and 6, the front frame l2 and slide trackare shown in detail. This frame is substantially similar to frame |3, inthat the shelf 24 is provided with a, longitudinally extending. groove53, forming the lower portion of the forward slide track. A top bar orrail 54 corresponds to the rail 3| of the rear frame I3, and is providedwith a longitudinally extending groove 55 in alignment with the groove53 and cooperating therewith to form the forward slide track. Theprimary difference between the frames l2 and I3 is that the, forwardframe I2 is provided with the centrally disposed plate |8 having theunobstructed window or opening H of a size to accommodate one of theslides l8. As will be observed from Figure 1, the projecting mechanism56 is so located that its several lenses are in alignment with thewindow l1, whereby the image on each slide is projected onto a suitablescreen (not shown) as the slides are shifted in the forward slide trackfrom one magazine'to the other.

The forward frame l2, similarly to the frame I3, is provided with aspring pressed bar 58 corresponding to the bar 21, and the inner wall ofthe groove 53 is cut away in front of the magazines to permit the slidesto be received and discharged from the slide track. This is also true ofthe upper grooves32 and 55.

Means for shifting the slides IS in the front and rear slide trackscomprise a pair of slide carriers 59 (see Figures 1, '1, 8, and 9). Eachslide consists of a plate-like member ofsubstantially rectangularformation having a relatively thick section 88 and a relatively narrowsection 6|. When it is desired to utilize relatively thick slides, suchas those having metal frames as illustrated in the drawings, each slidecarrier is mounted in its respective slide track, as shown in Figures 1and 6. In this use of the slide carrier the inner edge 62 of the thickerportion 66 is adapted to engage a side edge of a-front slide immediatelyafter it is pushed .from the front of the magazine into the slide track.

When it is desired to utilize slides which are relatively thin ascompared with those having metal frames, such as, for instance, thosehaving paper or cardboard frames, section 6| of the slide carrier isutilized. As shown in Figures 7 and 8, the line dividing the thick andthin sections forms a shoulder 63, which is adapted to engage the edgeof the slide as it emerges from the front of the magazine. In otherwords, the section 6| forms a pocket within which the thin slide isadapted to fit.

In using the thin slides, each slide carrier must be removed from theapparatus and its position completely reversed, as distinguished fromthat shown in Figure 1. That is,'the thin shouldered portion will faceinwardly toward its respective magazine, so that the front slide in themagazine will be pushed into contact with the thin section 6|, wherebythe outer side edge of the thin slide will be engaged by the shoulder 63and shifted into the slide track by the carrier. It will be observedthat the thin section 6| is not solid, as is section 60, but hassubstantially all of its interior portion cut out to form a pair of'legs64. The slide carrier is constructed in this manner to accommodate thecarrier operating means for the front carrier, as will be hereinafterdescribed. Otherwise the thin section could consist of a solid plate,the same as the section 60.

Power for actuating the slide carriers is taken from a main power shaft65, which extends outside and longitudinally of the frame ll. shaft isjournaled at one end in an upstanding arm 66 supported on the main frame(see Figure 1), and at the other end in a yoke 61 carried by a bracket61 extending outwardly of and supported from the shelf 25. The shaft 65is provided with a crank arm 68, to one end of which is pivotallysecured a connecting rod 59. The other end of this rod is detachablyconnected to the rear slide carrier.

The means for detaching the connecting rod 69 to the carrier comprises aflattened head 10, within which is mounted a screw bolt 1|. bolt isfreely rotatable in the head 10 but is locked thereon to preventdisplacement and loss of the bolt. Each slide carrier is provided with athreaded opening 12 adjacent the outer edge of its thickened portionportion of the screw bolt. If it is desired to remove the slide carrierfrom the rear slide track, it is merely necessary to grasp the knurledhead 13 of the screw bolt and unscrew the bolt from the slide cap. Thecarrier may then be slipped out of the frame i 3, and if it is desiredto re insert it to accommodate thin slides, it should be reversed, ashereinbefore described, so that the thin section 6|, including the legs64, will engage the grooves 32 and 26. The screw bolt is then screwedinto the threaded opening 14. This opening 14 is so arranged that itwill readily al gn with and accommodate the bolt 1|. In other words,when'the slide carrier is reversed to accommodate the thin slides, theopening 14 will be in the same relative position as was the opening 12.

The shaft 68 is connected through a suitable reduction unit 15 to anelectric motor 16. Operation of this motor will rotate the shaft 65,

This

This r for receiving the threaded which, in turn, will rotate the crankarm 68, thereby oscillating the connecting rod 66 and reciprocating theslide carrier in the rear slide track. The throw of the connecting -rod69 is such as to advance each slide a predetermined distance. In thepresent construction, the arrangement is such that the slide will travelsubstantially its own length so that it will clear the space in front ofthe magazines and permit the next slide to be pushed into position inthe slide track. In the position shown in Figure l, the slide carrierhas completed its inward travel and has started on its outward strokeand will be moved to the extreme left of the magazine i5 to permit thenext slide to be shoved into operative carrier-engaging position.

Referring now to Figure 6, it will be observed that the means forreciprocating the slide carrier 59 in the front slide track comprises arotary disk 11 fixed to one end of the main power shaft 65; A connectingrod 18 has one end thereof eccentrically and pivotally connected to thedisk 11. The other end of the rod is provided with a screw bolt 19corresponding to the screw bolt This bolt is detachably connected to thefront slide carrier, in the same manner as the screw bolt 1| isconnected to the rear slide carrier.

It will be observed that with this construction, the disk 11 and theconnecting rod 18 will effectively actuate the front slide carrier sothat the away, as illustrated, As shown in Figure 6, this constructionpermits the arms 64 to straddle the shaft 65 without contacting thesame. The extreme inner portion of the thin section is also providedwith a recess to further accommodate the shaft 55 and prevent anycontact of the carrier with the shaft as the carrier reaches its extremeouter position.

Since the shaft 65 and disk 11 constitute an obstruction for preventingthe front carrier from being slipped out of the slide track in a mannersimilar to the rear slide carrier, means are provided to permit thefront carrier to be lifted out of the-top of the track. This meanscomprises a gate 8| (see Figures 1 and 6) pivoted at its inner end onthe top bar or-rail 54, so that it may be swung upwardly, as shown indotted lines. When the gate 8| is raised, the carrier 59 may be removedfrom the frame by loosening the bolt 19. The outer end of the gate 1! issupported upon the post 46, and a pivoted latch 82 is adapted to engagean inwardly extending arm 83 on the gate to maintain the latter in itslowered operative position. A coil spring 84 normally urges the latch 82into locking position with the arm 83. It is to be understood that thegate 8| actually constitutes a continuation of the rail 54, and of thetop groove 55 of the front slide track.

The end of each slide track, which is adjacent ed between the arms intosuch position by the slide carriers. This stop means, in each instance,comprises a pin 85 (see Figures 1 and 3) which is slidably mounted in ablock 88 positioned on its respective shelf. For instance, the left-handend of Figure 3 illustrates the front of the slide changing mechanism,and the block 88 is illustrated as being mounted on the shelf 24. Thepin 85 is provided with an Integral enlargement 81 adjacent its innerend, and a coil spring 88 is mounted on the pin between the block 88 andenlargement 81, and normally urges the inner end of the pin intoengagement with the post 42. The pin, therefore, constitutes a stop forlimiting the movement of and positioning a side so that it may besubsequently pushed into the rear end of the supply magazine I5. If, forany reason, it is desired to remove this slide or any other slide in theslide track, it is merely necessary to grasp the head 89 of the pin andpull it outwardly against the tension of the spring 88, thereby clearingthe slide track and'permitting one or more of the slides to be removed.Upon release of the head 89, the spring 88 will return the pin to itsnormany-operative position with its inner end abutting the post 42. Asstated above, a similar pin 85 is mounted on end of the receivingmagazine I4.

The means for pushing the slides into the rear end of each magazine asthey are transferred thereto on the adjacent slide track, consists ofsets of substantially similar pusher mechanisms. Referring to Figures 1to 5, it willbe observed that this mechanism comprises a supporting post98 having laterally extending blocks 9I and 92 at its upper and lowerends, and upon which are pivotally mounted a pair of pusher arms 99- and94, respectively. These arms are of substantially channel formation incross section, the arm 83 having a pair of similar downwardly extendingflanges 95, the rear ends of which are pivoted to the block 9|. Sincethe top surface of the block 9| is flat, this will constitute a stop forengaging the base of the arm 93 and limit the downward movement of thearm. The same is true of the arm 94, this arm being provided withupwardly extending flanges 96, the rear ends of which embrace the rearend of the block 92 and are pivoted thereto.

The free forward ends of the arms are provided with flat slide engagingsurfaces 91, 98, respectively, which are adapted to contact the upperand lower portions of a slide after it is shifted into position in rearof a magazine, and push the slide forwardly into the magazine when thearms are operated. A coil spring 99 is positioned between and connectsthe arms 93 and 94, normally maintaining them in substantiallyhorizontal position, as shown in Figure 5. Both sets of flanges 95 and98 are cut away to provide reduced portions I88 and I8I, respectively,adjacent the forward ends of the arms. This is to provide suiflcientclearance to allow each slide to be shift- 93 and 94, asthe slide ismoved into alignment in rear of its respective magazine. The flange ofeach pusher arm is also formed with an inclined or beveled portion I82,extending from its reduced area to its flat slide engaging surface. Thisis to permit the arms to slide rearwardly over the upper and lowersurfaces of a slide when the pusher mechanism is moved rearwardly toslide pushing positioni In order to guide the pusher mechanism in itsforward and rearward paths and to prevent any lateral movement thereof,I provide upper and the shelf 25 adjacent the rear lower guide means forengaging and guiding. the arms 88 and 94. Referring to Figure 2, it willbe observed that a block I88 is mounted on the rail 8| directly abovethe entrance to the magazine I4. This block positioned passage I84 forreceiving and guiding the upper pusher arm 98. The reduced portion I8Iof the lower pusher arm 84 is locatedbelow the shelf 25 (see Figure 4,),and this shelf is provided with a pair of transversely extending slotsI85, within which the pusher engaging end portions 91 and 88 areslidably mounted. These slots are extended by cutting away portions ofthe longitudinal frame member I9 (see' Figure 4) so that the lower armmay be moved forward sufllciently to push a slide into the rear end ofthe magazine I4.

The means for actuating the pusher mechanism for magazine I4 comprises arocker arm I88, which extends outside of, and across, the rear slidetrack and is pivotally mounted on a rearwardly extending support I81(see Figure 1). This arm is provided with an upper section I88, theintermediate portion of which is pivotally connected to a pair of earsI89 formed integral with the post 98 of the pusher mechanism. The outerfree end of the section I88 extends -beyond the end post II8 mounted onthe drive shaft 55. ,A guide member III (see Figure 2) is mounted ontheshelf 25 and is provided with a slotted portion adapted to receive. andprevent lateral movement of the section I88 as it is being rocked bythecam II8.

With the construction as thus far described, and assuming that the shaftis rotating the cam II8, this action will actuate the rock shaft I98 andimpart a rocking action to the section I88. Since the pusher mechanismis pivotally connected to the section I88, the arms .93 and 94 will bemoved forwardly and rearwardly in their respective guides. The operationof the different elements are so synchronized that when the arms 93, 94,have completed their forward movement in which a slide has been pushedinto the rear end of the magazine I4, the cut-away or reduced portionsI88 and IM of the arms will be in register with the slide track, wherebythe slide carrier will operate to shift a slide between the pusher armsinto alignment with the rear end of the magazine. Thereafter rearwardmovement of the section I88 will also effect a rearward movement of thepusher arms. Since these arms are capable of outward pivotal movementagainst the tension of the spring 99, and since the inclined or beveledportions I82 of the arms connect the reduced portions of the arms, thesearms will separate sufiiciently to move rearward- 1y over the upper andlower edges of the slide which has just been hifted between the arms. Inother words, the pusher arms will travel rearwardly to a position in therear of the slide, and as soon as they have cleared the slide, thespring 99 will contract the arms to their normal-pusher position,whereby the flat slide engaging portions 91' and 98 will be directly inrear of the slide, and in position to push the slide forwardly into themagazine. This operation is repeated during the actuation of the machineas the slides are constantly shifted from the rear slide track intoalignment with the magazine l4.

It is to be understood that a similar pusher mechanism is mounted at therear of the magazine I5 for pushing the slides into this magazine asthey are received from the front slide is provided with a centrally 88and into the path of a cam I back and forth in the guides.

track after being exhibited. The pusher arm and guide means areidentical with those above described, the only difference being in theconnections for reciprocating the pusher mechanism In this connectionthe rocker arm I06 functions as the means for actuating the front pushermechanism, as

well as the rear pusher mechanism. The rocker arm is provided with asection II2 on the other side of the pivot from the section I08. The endof section II2 is-pivotally connected to one end of a longitudinallyextending rod I I3, which is mounted longitudinally of and below itsrespective frame member I9 (see Figures 1 and 3).

The other end of this arm extends through suitable openings in the framemembers I9 and 22, and also through an opening in a supporting platformII4 mounted on the frame 22 (see particularly Figure 3). The post 90 ofthe forward pusher mechanism is removably supported upon a member H5,which passes through an opening in the lower block 92 of the post, andalso through a hole in an inwardly extending lug H6 of the post. Thelower end of the member H is provided with a head 1, upon which thelower pusher arm 94 rests. This head has formed therein a transverseopening through which the extreme reduced end portion of the rod II3projects. A set screw II 8 is threaded into the lower end of the headII? to clamp the end of the rod H3 thereto. An opening H9 is formed inthe supporting platform M4 to permit loosening of the set screw, H8 whenit is desired to remove the pusher mechanism from the rod II 3.

The construction and operation of the rocker arm I06 is such that as thecam rocks the sections I08 and H2 about, the central pivot of thearm,'this motion will be transmitted to both ,of the pusher mechanismswhereby they will be actuated to simultaneously push slides 'into therear ends of the magazines i l and 55. As described hereinabove, thepusher mechanism and the slide carrier mechanism are so synchronizedthat, as the slide carriers are operated to shift the slides in thefront and rear slide tracks, the pusher arms will be held momentarilystationary in their forward positions to receive slides between theirrespective arms. As the movement of each slide carrier is reversed, eachpusher mechanism will be shifted rearwardly so that its arms will clearthe slide and come to rest directly in rear of the slide, and thereby bein position to push the slide forwardly into its respective magazinewhen the arms are again moved forwardly. As the arms move forwardly, theslide carriers will operate to move slides in the tracks and again shiftthe end slides between the arms of the pusher mechanism. Thissynchronized operation will continue to shift the slides in the slidecarriers and magazines so that an entire series of slides may be readilyexhibited as desired. In order that the rocker arm I 06 will always bemaintained in operative engagement with the cam III], I provide a coilspring I20. One end of this spring is connected to an intermediateportion of the section. I08, while the other end is connected to astationary post I2I rigidly connected to the motor base I22. It will beobserved that the cam is formed with a gradually inclined surface and anabrupt drop (see Figure 1). This is for the purpose of moving the pusherarms forward at a uniform speed and then quickly returning the arms totheir slide pushing position. It is to be understood aaeaeeo that therelative movement of the pusher arm may-be varied as desired by changingthe cam track. I

It will be observed that each set of pusher arms 93 and 94, togetherwith their supporting post 90, are directly connected to theirrespectiveoperating mechanism and that no spring means are employed for constantlyurging the pusher arms into engagement with th rearmost slides in themagazines or for exerting spring pressure upon the slides. With thepresent construction, this is unnecessary, since the pusher mechanism isdesigned to utilize and take advantage of the resiliency and springinessof the slides themselves to effect an efficient operation of theapparatus.

I have ascertained that, with a magazine full of slides having metalframes as illustrated in the drawings, the sprlnginess of the frames issuch that they will be compressed and expanded during eachv forward andrearward movement of the pusher mechanism. That is, each frame iscapable of a certain amount of transverse compression and expansion whenacted upon by the pusher arms. Therefore, the total compression andexpansion of all of ,the slide frames in a magazine is considerable andeliminates the nethe pusher mechanism with the spring-like action isadequately transmittedfrom the rearmost to the front slide in themagazine.

Because of this flexibility of the slides, it isnot necessary that anyspecified number by placed in each magazine in order to insureanefiici'ent operation of the apparatus. That one or more slides may beinserted or removed from a magazine as desired, the only requisite beingthat there be a suilicient number of slides in a magazine to permit thepusher mechanism to transmit the pushing action to the slides at thefront of the magazine.

I have also found that this same springiness and resiliency is inherentin slides having paper or cardboard frames, and that such slides operateequally as well in my apparatus, as those having metal frames. Thisspringiness in the paper frames is undoubtedly due to the fact that airpenetrates between adjacent slides and forms air pockets. Furthermore,the porosity of the paper permits penetration of the air into the paperor cardboard itself and assists in the springy and resilient action ofthe slides when acted upon by the pusher mechanism. It is to beunderstood that slide frames made of other materials having thesecharacteristics may be used with equal success in the present apparatus.

The slide changing mechanism as thus far described provides a veryeffective machine. I have found, however, that when slides with metalframes are used, these slides are apt to become jammed in the machine,particularly when one slide is being shifted laterally out of the frontof a magazine relative to its adjacent slide. This is caused primarilybecause of the fact that many of the metal frames have warped or belliededges which project outwardly from the normal plane of the casing orframe. Such a warped frame is shown at I23 in Figure 12 of the drawings.If a slide having a warped frame of this character is positioned in oneof the magazines so the slide which is being shifted latbecome lockedagainst the warped slide and therebyproduce a jamming action of theentire machine, since the slide carrier will be unable to shift thefront slide wholly into the slide track. This jamming action may also becaused by raised portions or other projections on the frame of eitherthe slide which is being shifted, or its adjacent slide.

I have incorporated into the present machine means for eliminating thisobjectionable feature and for preventing looking or jamming of theslides as they are shifted laterally out of the front of one magazineinto its adjacent slide track. This is accomplished by effecting apositive agitating or rocking action of the slides, only when they reachthe front of the magazine, but as they gradually approach the front endof the magazine.

Referring to Figures 13 to 16, there is disclosed in detail a mechanismfor accomplishing this agitating or rocking action. While differentmechanisms may be employed to separate and rock the slides, I have foundthat this may be very effectively accomplished by providing a cammechanism on the inner face of the thick portion of each slide carrier.This cam mechanism comprises a pair of cams I24 and I25 (see Figure 9).Cam I24 is rigidly secured to the upper inner surface of the thickportion 60 of the slide carrier, while cam I25 is mounted in alignmentwith cam I24 adjacent the lower inner surface of the carrier. Each camis provided with a relatively fiat slide engaging surface, this surfacebeing highest intermediate its ends and sloping downwardly at each endto the inner face of the carrier.

p.- rent that erally will I have found that a cam mechanism formed in.

this manner will transmit a series of rocking actions or motions to theslides as the slide carrier is reciprocated backand forth. These rockingactions will cause a separation of both edges of the front slide fromits adjacent slide just prior to the shifting of the slide by thecarrier into its respective slide track. Figure 13 is a view showing theslide carrier 59 just before it clears the outer side of the magazine.This movement not only effects a final rocking action on the frontslide, but in varying degrees on a number of the slides in rear of thefront slide. It will be observed that this rocking action positivelyseparates the inner edges of the slides.

Figure 14 discloses the slide carrier in its extreme outward positionjust prior to its return movement for shifting the front slide in theslide track. Figure 15 shows the action of the cams as the slide carrierstarts its initial shifting movement. This action, similarly to thatshown in Figure 13, positively separates the inner edges of a number ofslides in back of the front slide. It, furthermore, raises the outeredge of the adjacent slide from that of the slide which is being shiftedby the slide carrier, so that' auy warped portions or projections oneither one or the other of these slides will be positively separated toprevent any jamming or locking of one slide relative to the other whichmight prevent the front slide from being entirely shifted away from themagazine out of the path of the next slide.

Figure 16 shows the slide carrier at the end of its inward movement. Inthis position, it will be observed that the outer end of the slide whichis being shifted is positively separated from its adjacent slide so asto insure against any jamming or looking action between the slides. In

not

view of the fact that this rocking action not only affects the extremefront slide, but also a number of slides which are being advanced towardthe front of the magazine, it will be apparent that the cam mechanism isvery effective, since the slides are being constantly separated one fromanother as they gradually advance into the front of the magazine.

It is, of course, to be understood that the rocking action issynchronized with the action of the pusher mechanism in the rear of eachmagazine. In other words, the pushing action of the pusher mechanism atone end of the magazine, is resiliently transmitted to the front of themagazine and cooperates with the rocking action of the cams to effectthe separation of the slides as they approach the front of the magazine.This rocking action is somewhat dependent upon the resiliency andspringiness of the slide frames. At least, this resiliency of the framesgreatly facilitates the rocking action, which, in turn, produces theseparation of the slides as they approach the front of the magazine.

In addition to the cam mechanism for effecting the rocking action on theslides, I provide a further means for assuring that the slides will notjam or catch in the mechanism as they are being transferred from thefront of a magazine to its adjacent slide track. Referring to Figure 2,it will be observed that the post 33 located interiorly of the front ofmagazine I5, has its front face 33' reduced in thickness intermediateits ends to provide upper and lower shoulders "33. In other words, allof the surface of the front face 33' between its upper and lower edgesis of less thickness than the upper and lower surfaces. With thisconstruction, and assuming that the rear face of the frame of the frontslide is warped or bellied as illustrated in Figure 12, the reducedintermediate portion of the post jam the slide against further lateralmovement into the slide track. This objectionable feature is, of course,obviated by the present construction. The post 45 in the front frame I2(see Figure 6) is likewise provided with a reduced intermediate portion45' to. take care of warped or defective frames.

Any suitable switch mechanism may be utilized to control the operationof the slide changing mechanism, the main requisite being that theoperator will have a flexible control of the apparatus. That is, thatthe slides may be exhibited throughout either a short or long interval,as desired. The switch mechanism of the present construction is designedto accomplish this result, and comprises a main switch I26 mounted inthe motor support or base I22 (see Figures 1 and 26). Thisbase alsoaccommodates an outlet plug I2'l for plugging in the projector. The maincircuit of the apparatus is designated by the wiring I28, and this isconnected to the motor I5 and to a cam-actuated switch arm I29 of theswitch I29. The switch arm I28 is normally spring pressed outwardlyagainst. the cam IIII. This cam carries an arcuate strap I30, which,upon rotation of the cam, engages the arm I29, and moves it sufficientlyto break the circuit to the motor. The strap is so positioned that thecircuit is broken just as a slide is presented to the circuit will againthe window I1. Therefore, assuming that the circuit is closed, and. thatthe arm I29 is not in contact with the strap I30, the cam will berotated and the slide changing mechanism actuated to shift one slideaway from the projector and a new slide into the window in position tobe exhibited. As the new slide is shifted into the window I1, the strapI30 will engage the. arm I 29, moving it sufllciently to open the switchI29, thereby stopping the slide changing mech-- anism whereby the newslide may be exhibited as long as desired.

The means for closing the circuit to the motor to again operate theslide changing mechanism comprises a second switch element I3I, which isin a circuit I32 that bridges the switch I29 (see Figure 26). Therefore,when the button I33 is depressed, it closes the main circuit and therebyenergizes the motor to operate the mechanism. As soon as the cam hasbeen rotated sufliciently to move the strap I30 011 of the arm I29, thebutton I33 may be released, since the circuit will be closed until thestrapagain rotates around to a position to contact and move the arm I29.Assuming that the button I33 has been released, be broken so that thenew slide may be exhibited as long as desired. It is to be understood,however, that if the operator wishes to shift several slides quicklypast the window I1, it is merely necessary to maintain the button I 33depressed. This will keep the main circuit closed, regardless of theposition of the strap I30 and switch arm I29, so that subsequent slidesmay be quickly shifted past the window. This shifting actionwillcontinue until the switch button I33 is released. It will be apparent,therefore, that the present electrical connections provide a flexibleunit which will permit the operator to exhibit the slides for either ashort or long period, as desired.

In the event that certain of the slides have been accidentally raised orlifted out of their normal positions in the magazines, I have providedmeans for forcing such slides downwardly into their correct positionsprior to their movement from the front of a magazine into the slidetrack. This is accomplished by mounting on each of the top rails or bars3| and 54, a block I34 (see Figures 1 and 3). Each block is providedwith a downwardly and forwardly inclined or beveled face I35, which ispositioned directly above the front extremity of its respectivemagazine. With this construction, and assuming that a slide is raisedabove the other slides as it approaches the front of the magazine, thetop edge of the. slide will engage the inclined surface I35 and begradually lowered to its normal position where it will correctly passthrough the front of the magazine into the slide track. The block I34 ismounted on the free end of an arm I33, this arm being pivoted to itsrespective top rail so that it may be moved about its pivot from theposition over the magazine to permit the latter to be removed from theframe II.

While it is preferred that the mechanism be motor operated, this is notessential, since a manually actuated means may be employed, if desired.In this connection, I have illustrated a modified structure in Figure17, for manually rotating the drive shaft 65 and cam H0. The end of theshaft is connected to a flexible cable or wire I31 which, in turn, isconnected to an operating handle I38. The cable I31 is encased in aflexible casing I39, the outer end of which is surrounded by a rigidsleeve I40.

Rotation of the handle I 33 will transmit rotary motion to shaft 35 andthereby actuate the apparatus. As a safety measure. a clutch is providedbetween the cam H0 and motor 13 to prevent damage to the shaft in theevent any of the operating parts should become jammed, Thi clutchcomprises a clutch element I H fixed to the, shaft section I42, thesection being separated from the shaft 33 at a point within the clutch.

A second clutch element I42 is splined or keyed to the shaft 35 and hasa cam surface normally held in engagement with a complementary camsurface on element MI by a spring I 44 positioned between the elementI43 and the yoke 31. During normal operation of the apparatus, theclutch will operatively connect shaft section I42 to shaft 35. However,if shaft 33 or any element associated therewith is jammed, the camsurface on clutch element I will rotate relative to that of cam elementI43 and thereby prevent damage to the mechanism. This clutch mechanismis also applied to the hand operated structure shown in Figure 17.

The motor base I 22 is rigidly secured to the main frame II by reason ofthe connection of its projector is adjustably supported. Openings I50 inthe lower cross frame 22 are provided to accommodate means forconnecting the projector to the front of the frame.

Referring now to Figures 18 to 22, ther is disclosed in detail one ofthe trays or magazines. This tray is of substantially channel formationin cross section and comprises a base I BI and side walls I52. The baseis provided with a pair of spaced longitudinally extending inwardlypressed portions forming ridges I53. Each side I52 is likewise providedwith an inwardly pressed portion forming a longitudinally extendingridge I54 which cooperates with the ridges I53 to facilitate the passageof the slides through the magazines.

It will be apparent that the slides contact only these ridges as theypass through the magazines, and the travel of the slides is, therefore,greatly assisted, since the frictional resistance is considerablyreduced. there being only the four contact surfaces which the slidesengage as they pass through the magazines.

In view of the fact that each tray is open ended, I have provided acover I55 for the tray, to be used when it desired to remove a magazinefrom the apparatus. This cover comprises a top I56. side walls I51, andend walls I58. Each side I51 is provided with projecting ridge I59adjacent its lower end, which, when the cover is applied to the tray, is

" dentally slipping out between and 21, so that the ridges I59 of thecover and thereby lock and securely maintain the slides in the tray asit is removed from the main frame ll.

In order to prevent any of the slides from accithe ends I58 of the boverand the ends of the tray, I further provide to include any means forsupporting and guiding a slide after it leaves the magazine. It is to bemeans for locking these ends against distension or expansion. In thisconnection, each end of the base l5l of the tray is cut out to provide atongue i611 having formed therein a transverse slot IBI. Each end I58 isalso extension I62 adapted to align with its respective slot l6l as thecover is applied to the tray. As the channels and ridges in the coverand tray are moved into locking engagement, the extensions "52simultaneously move into the slots IGI and thereby lock the ends I58from outward movement. This prevents any accidental removal of \theslides from the ends of the tray.

In Figures 23 to 25, I have illustrated a spacer which may be utilizedin event that the operator is not supplied with sufiicient slides tocompletely fill both magazines. In this event, or if the series whichthe operator is exhibiting, comprise only a few slides-a pair of thesespacers may be effectively utilized. Each spacer consists of a threadedrod I63 which is telescoped within an internally threaded sleeve I64.The free end of the rod "53 has rigidlyconnectedthereto a head I 65whose outer face is provided with a border of resilient materiallfifi'suchQas rubber. A similar head I6! is secured to the'f'ree end ofthe sleeve or tube I64, but in this instance, the head is rotatablymounted on the endof the sleeve (see Figure 25) thereto.

Assuming that it is desiredto utilize a pair of spacers, each one isinserted into its respective magazine. In view of the fact that the headIE1 is rotatably mounted on the sleeve, it is merely necessary to rotatethe sleeve to either expand or contract the spacer to correctly'flll thespace in the magazine. In other words-because of this particularconstruction, it is not necessary to constantly remove the spacer androtate the sleeve relative to the rod, in order to provide the correctfit between the spacer and the slides in the magazine. Due to theadjustability of the spacer, it is capable of being telescoped to occupythe space of only a few slides, or it can be expanded so as to occupy asmuch of the area of a magazine as is necessary. Assuming that a spaceris inserted in magazine l5, the slides to be exhibited will be placedbetween the front of the magazine and one of theheads of the spacer. Thesleeve or tube I64 is then rotated to take up an clearance, the. rubberborder I66 forming a resilient cushion between the spacer and slides. Itwill, of course, be necessary for the operator to watch the travel ofthe slides so as to shut off the machine whefiethe front of the spacerreaches the extreme front of the magazine. Otherwise, there would be ajamming action which would prevent the operation of the slide changingmechanism. of course, the ideal arrangement is to have the magazinescompletely filled with slides such as disclosed in Figure 1 of thedrawings, and the spacers are used only where the series to be exhibitedis very small or the operator is not provided with suflicient slides tocompletely fill the magazines.

It is to be understood that the term "slide track" in the claims is tobebroadly interpreted instead of being rigidly secured provided with anfurther understood that the invention is not limited to details ofconstruction shown in the drawings and described in the specification,and that the phraseology employed in the specification is for thepurpose of description and not of'limitation.

I claim:

.1. In a device of the character described, a magazine for holding aplurality of picture slides, a slide track mounted transversely of andconnecting one end of the magazine, a slide carrier movable back andforth in advance of the magazine and adapted to engage an edge of theend slide in the magazine and transfer it to the slide track, and a pairof spaced cams mounted on the inner face of said slide carrier andadapted to transmit a rocking movement to the second slide in themagazine as the slide carrier is shifting the front slide to the slidetrack, whereby the front slide is permitted to move freely out of themagazine away from the second slide.

2. In a device of the character described, a magazine for holding aplurality of picture slides, a slide track mounted transversely of andconnecting one end of the magazine, a slide carrier comprising a...plate-like member movable back and forth in advance of the magazine andadapted to engage an edge of the end slide in the magazine and transferit to the slide track, and a pair I of cams mounted on the inner face ofthe carrier, one. cam being located adjacent the upper inner edge andthe other cam located adjacent the lower inner edge of the plate-likemember, said cams being adapted to transmit a rocking movement to thesecond slide in the magazine as the slide carrier is shifting the frontslide to the slide track, whereby the front slide is permitted to movefreely out of the magazine away from the second slide.

3. In a device of the character described, a magazine for holding aplurality of picture slides, a slide track mounted transversely of andconnecting one end of the magazine, a slide carrier comprising aplate-like member movable back and forth in advance of the magazine andadapted to engage an edge of the end slide in the magazine and transferit to the slide track, and a cam mounted on the inner face of saidplate-like member adjacent the inner edge thereof, said cam having arelatively fiat slide engaging surface, said surface being highestintermediate its ends and sloping downwardly at each end to the face ofthe plate, said cam being adapted to transmit a rocking movement to thesecond slide in the magazine as the slide carrier is shifting the frontslide to the slide track, whereby the front slide is permitted to movefreely out of the'magazine away from the second slide.

4. A reversible slide carrier for use with a slide changing apparatusand adapted to transfer .slides from a magazine to a slide trackpositioned transversely of and connected to the magazine, said carriercomprising a plate-like member having a relatively straight edge adaptedto engage the edge of a slide and shift it from the magazine to theslide track, said member when reversed having a section of lessthickness than the rest of the plate-for accommodate ing and shiftingrelatively thin slides.

5. A reversible slide carrier for use with a slide changing apparatusand adapted to transfer slides from a magazine to a slide trackp'ositioned transversely of and connected to the magazine, said carriercomprising a plate-like member having a relatively straight edge adaptedto engage the edge of a slide and'shift it from the magazine to theslide track, said member having a section of less thickness than therest of the plate, the line dividing the two sections forming a shoulderextending transversely of the plate and adapted when the member isreversed to engage an edge of a relatively thin slide and shift it tothe slide track.

6. A slide carrier for use with a slide changing apparatus and adaptedto transfer slides from versely of and connected to the magazine, said.

carrier comprising a plate-like member having a relatively straight edgeadapted to engage the edge of the front slide and shift it from themagazine to the slide track, the side of the plate facing the magazinebeing provided with cam means for engaging an adjacent slide in themagazine and transmitting thereto a rocking action relative to the frontslide in the magazine to permit said front slide to move freely out ofthe magazine away from its adjacent slide.

8. A slide carrier for use with a slide changing apparatus and adaptedto transfer slides from a magazine to a slide track positionedtransversely of and connected to the magazine, said carrier comprising aplate-like member having a I relatively straight edge adapted to engagethe edge of a slide and shift it from the magazine to the slide track,and spaced cams mounted on the side of the plate facing the magazine,one cam being located adjacent the upper inner edge and the other camlocated adjacent the lower inner edge of the plate, said cams beingadapted to engage a slide in the magazine and transmit thereto a rockingaction relative to the front slide in the magazine to permit said frontslide to move freely out of the magazine away from its adjacent slide.

9. In a device of the character described, a supporting frame, a pair ofspaced magazines mounted on the frame, a pair of slide tracks, eachconnecting adjacent ends of the magazines and forming therewith a closedcircuit for allowing the slides to be moved from one magazine toanother, means for shifting the slides on the slide tracks from thefront end of one magazine to the rear end of the other magazine, andmeans associated with the rear end of each magazine for pushing theslides forwardly in the magazines as the foremost slide is being movedout of the front end thereof, said means including a pair of upper andlower pusher arms adapted to engage the rearmost slide and move it andthe other slides forwardly in the maga- 'zine, cooperating means on saidarms for permitting a slide from the adjacent slide track to be shiftedbetween said arms in rear of the front ends thereof when said arms arein engagement with the rearmost slide, and means for permittingseparation of said arms whereby slide and in position to push said slideforthey may be moved rearwardly of the shifted 75 wardly into themagazine.

10. In a device of the character described, a supporting frame, a pairof spaced magazines mounted on the frame, a pair of slide tracks, eachconnecting adjacent ends of the magazines and forming therewith a closedcircuit for allowing the slides to be moved from one magazine toanother, means for shifting the slides on the slide tracks from thefront end of one magazine to the rear end of the other magazine, andmeans associated with the rear end of each magazine for pushing theslides forwardly in the magazine as the foremost slide is being movedout of the front end thereof, said means including a pair of upper andlower pusher arms adapted to engage the rearmost slide and move it andthe other slides forwardly in the magazine, the forward free ends ofsaid arms having flat slide engaging surfaces, said arms having reducedportions in rear of said slide engaging surfaces to allow a slide fromthe adjacent slide track to be shifted between said arms when they arein engagement with the rearmost slide, 5

and means for permitting separation of said arms whereby they may bemoved rearwardly of the shifted slide and in position to push saidslideforwardly in the magazin.

11. In a device of the character described, a supporting frame, a pairof spaced magazines mounted on the frame, a pair of slide tracks, eachconnecting adjacent ends of the magazines and forming therewith a closedcircuit for allowing the slides to be moved from one magazine toanother, means for shifting the slides on the slide 1 tracks from thefront end of one magazine to the rear end of the other magazine, andmeans associated with the rear end of each magazine for pushing theslides forwardly in the magazine as the foremost slide is being movedout of the front end thereof, said means including a pair of pivotallymounted upper and lower pusher arms adapted to engage the rearmost slideand move it and the other slides forwardly in the magazine, the forwardfree ends of said arms having flat slide engaging surfaces, said armshaving reduced portions in rear of said slide engaging surfaces to allowa slide from the adjacent slide track to be shifted between said armswhen they are in engagement with the rearmost slide, each arm having anoutwardly inclined portion connecting the flat slide engaging surfacewith the reduced portion to permit it to slide rearwardly over theshifted slide and in position to push said slide forwardly in themagazine.

12. In a device of the character described, a supporting frame, a pairof spaced magazines mounted on the frame, a pair of slide tracks, eachconnecting adjacent ends of the magazines and forming therewith a closedcircuit for allowing the slides to be moved from one magazine tovanother, means for shifting the slides on the slide tracks from thefront end of one magazine to the rear end of the other magazine, andmeans associated with the rear end of each magazine for pushing .theslides forwardly in the magazine as the foremost slide is being movedout of the front; end thereof, said means including a post carried bythe frame and movable to and from the rear of the magazine, a pair ofpusher arms pivotally mounted upon opposite ends of said post and havingtheir free ends extending forwardly" and formed to provide flat slideengaging surfaces adapted to contact the move it and the other slidesforwardly in the rearmost slide and magazine, said post limiting theinward movement of the arms, and spring means connecting said arms andnormally urging them inwardly toward each other, said arms havingreduced portions in rear of said slide engaging surfaces to allow aslide from the adjacent slide track to be shifted between said arms whenthey are in engagement with the rearmost slide, each arm having anoutwardly inclined portion connecting the fiat slide engaging surfacewith the reduced portion to permit it to slide rearwardly over theshifted slide and in position to push said slide forwardly in themagazine.

13. In a device of the character described, a supporting frame, a pairof spaced magazines mounted on the frame, a pair of slide tracks, eachconnecting adjacent ends of the magazines and forming therewith a closedcircuit for allowing the slides to be moved from one magazine toanother, means for shifting the slides on the slide tracks from thefront end of one magazine to the rear end of the other magazine, meansassociated with the rear end of each magazine for pushing the slidesforwardly in the magazine as the foremost slide is being moved out ofthe front end thereof, said means including a. pair of upper and lowerpusher arms adapted to engage the rearmost slide and move it and theother slides forwardly in the magazine, said arms being constructed toallow a slide from the adjacent slide track to be shifted between saidarms in rear of thefront ends thereof when said arms are in engagementwith the rearmost slide, said arms being separable to permit them to bemoved rearwardly of the shifted slide and in position to push said slideforwardly into the magazine, and means for guiding said pusher arms intheir forward and rearward movements comprising a, block mounted on theframe above the upper arm and having a guide passage for receiving andguiding said upper arm, said frame having a slot formed therein andextending partially into the rear end of the magazine for receiving andguiding the lower arm.

14. In a device of the character described, a supporting frame, a pairof spaced magazines mounted on the frame, a pair of slide tracks, eachconnecting adjacent ends of the magazines and forming therewith a closedcircuit for allowing the slides to be moved from one magazine toanother, means for shifting the slides on the slide tracks from thefront end of one magazine to the rear end of the other magazine, meansassociated with the rear end of each magazine for pushing the slidesforwardly in the magazine as the foremost slide is being moved out ofthe front end thereof, said means including a pair of pivotally mountedupper and lower pusher arms adapted to engage the rearmost slide andmove it and the other slides forwardly in the magazine, the for wardfree ends of said arms having flat slide engaging surfaces, said armshaving reduced portions in rear of said slide engaging surfaces to allowa slide from the adjacent slide track to be shifted betwen said armswhen they are in engagement with the rearmost slide, each arm having anoutwardly inclined portion connecting the flat slide engaging surfacewith the reduced portion to permit it to slide rearwardly over theshifted slide and in position to push said slide forwardly in themagazine, and means for guiding said pusher arms in their forward andrearward movements comprising a block mounted on the frame above theupper arm and having a guide passage for receiving and guiding saidupper arm, said frame having a slot formed therein extendinglongitudinally of and partially into the rear end of the magazine, saidlower-- arm being mounted below the slotted portion of the frame, withits forward slide engaging portion projecting into the slot and movabletherein as the upper arm is moved in said block.

15. In a device of the character described, a supporting frame, a pairof spaced magazines mounted on the frame, a pair of slide tracks, eachconnecting adjacent ends of the magazines and forming therewith a closedcircuit for allowing the slides to be moved from one magazine toanother, means for shifting the slides on the slide tracks from thefront end of one magazine to the rear end of the other magazine, meansassociated with the rear end of each magazine for pushing the slidesforwardly in the magazine as the foremost slide is being moved out ofthe front end thereof, said means including pusher members adapted toengage the rearmost slide and move it and the other slides forwardly inthe magazine, means for actuating said pusher members, comprising arocker arm pivotally mounted intermediate its ends at one end of theframe, one of said pusher members being pivotally mounted on said rockerarm at a point in the rear of and in line with one of the magazines, arod mounted in the frame and extending longitudinally of the othermagazine and having one end thereof connected to the rocker arm, theother end of said rod being connected to the other pusher member, andmeans for actuating said rocker arm to alternately move each pushermember into engagement with the rearmost slide in its respectivemagazine.

16. In a device of the character described, a'

supporting frame, a pair of spaced magazines mounted on the frame, apair of slide tracks, each connecting adjacent ends of the magazines andforming therewith a closed circuit for allowing the slides to be movedfrom one magazine to another, means for shifting the slides on the slidetracks from the front end of one magazine to the rear end of the othermagazine, means associated with the rear end of each magazine forpushing the slides forwardly in the magazine as the foremost slide isbeing moved out of the front end thereof, said means including pushermembers adapted to engage the rearmost slide and move it and the otherslides forwardly in the magazine, means for actuating said pushermembers comprising a rocker arm pivotally mounted intermediate its endsat one end of the frame, one of said pusher members being pivotallymounted on said rocker arm at a point in the rear of and in line withone of the magazines, a rod slidably mounted in the frame below andextending longitudinally of the other magazine and having one endthereof connected to the rocker arm on the other side of its pivot fromthe first pusher member, and a second pusher member mounted at the rearof the other magazine and operatively connected to the other end of saidrod whereby operation of the rocker arm will alternately move eachpusher member into engagement with the rearmost slide in its respec ivemagazine.

1'7. In a device of the character described, a supporting frame, a pairof spaced magazines mounted on the frame, a pair of slide tracks, eachconnecting adjacent ends of the magazines and forming therewith a closedcircuit for allowing the slides to be moved from one magazine toanother, slide carriers positioned in said tracks for shifting theslides from the front end of one a said arm about its magazine to therear end of the other magazine, means associated with the rear end ofeach magazine for pushing the slides forwardly in the magazine as theforemost slide is being moved out of the front end thereof, said meansincluding pusher members adapted to engage the rearmost slide and moveit and the other slides forwardly in the magazine, means for actuatingsaid pusher members comprising a rocker arm pivotally mountedintermediate its ends at one 22. In a device of the character described,a frame, a magazine supported horizontally on the frame for holding aplurality of picture slides, a slide track mounted transversely of thefront end of the magazine and adapted to receive slides as they aremoved out of the magazine, and a stop block mounted on the frame at themagazine and above the normal slides, said block having a downwardly andforwardly extending beveled surface overlap the side walls of the tray,said cover havwalls connected only to the top, and interengaging meanson said tray and cover for locking the cover to the tray.

25. A spacer adapted to be inserted in a magspacer may be contracted orpositioned in a magazine.

26. In a device of the character described, a frame for supporting slidemagazines, a slide the latter to accommodate slides of diiferentthicknesses and track.

27. In a slide changing apparatus, a magazine 28. In a slide changingapparatus, a magazine 5 for holding a plurality of picture slides, aslide track mounted transversely of and connecting one end of themagazine, a slide carrier associated with the magazine and slide trackfor transferring the front slide from the magazine to the track, andmeans carried by said slide carrier for transmitting a rocking action tothe second slide in the magazine as the'front slide is moved out of themagazine into the slide track, to thereby effect a separation of saidslides longitudinally of the magazine andpermit the front slide to movefreelyout of the magazine away from the second slide.

29. In a slide changin apparatus, a magazine for holding a plura y ofpicture slides, a slide track mounted transversely of and connecting oneend of the magazine, a slide carrier associated with the magazine andslide track for transferring the front slide from the magazine to thetrack, and means carried by said slide carrier for transmitting arocking action to the second slide in the magazine as the front slide ismoved out of the magazine into the slide track, to thereby efiect aseparation of said slides longitudinally of the magazine and permit thefront slide to move freely out of the magazine away from the secondslide, said lastmentioned means also adapted to transmit a. rockingaction in varying degrees to slides in the magazine back of the secondslide, whereby the slides are given a preliminary'rocking movement toprevent adjacent slides from adhering to each other as they graduallyapproach the front of the magazine and the slide track.

30. In a slide changing apparatus, a magazine for holding a plurality ofpicture slides, a slide track mounted transversely of and connecting oneend of the magazine, a slide carrier associated with the magazine andslide track for transferring the front slide from the magazine to thetrack, and cam mechanism mounted on said carrier for transmitting arocking movement to the second slide in the magazine as the front slideis moved out of the magazine into the slide track to thereby effect aseparation of said slides longitudinally of the magazine and permitthe'front slide to move freely out of the magazine away from the secondslide.

JOSEPH A. DARWIN.

